TypeScript 4.2 has changed its emitted syntax for synthetic constructors
when using `downlevelIteration`, which affects ES5 bundles that have
been downleveled from ES2015 bundles. This is typically the case for UMD
bundles in the APF spec, as they are generated by downleveling the
ESM2015 bundle into ES5. The reflection capabilities in the runtime need
to recognize this new form to correctly deal with synthesized
constructors, as otherwise JIT compilation could generate invalid
factory functions.
Fixes#41298
PR Close#41305